{"title":"Load-Balancing Techniques for 5G Millimeter-Wave Distributed Antenna System","authors":"Teppei Oyama, Takashi Seyama","doi":"10.1109/VTC2021-Spring51267.2021.9448953","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448953","url":null,"abstract":"5G and beyond 5G is an emerging technology used to overcome the increasing mobile traffic triggered by new services. Utilization of millimeter wave is one of the key technologies for 5G NR to address radio resource shortage, especially below the 6-GHz band. However, compared with <6-GHz bands, millimeter wave is efficiently blocked by structures. Therefore, adjustments are required to make radio links line-of-sight. Moreover, the spatial user distribution is not uniform; there are hot spots, and the spatial user distribution changes with time. In this paper, we focus on millimeter-wave distributed antenna systems (mmWave DAS), which solve the issues associated with radio propagation of millimeter wave, and developed an algorithm to solve the mobile traffic imbalance between cells caused by nonuniform user distribution. The proposed algorithm improves the fairness of the system throughput using a system-level simulation.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133912701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keming Feng, Yijian Chen, Yu Han, Xiao Li, Shi Jin
{"title":"Passive Beamforming Design for Reconfigurable Intelligent Surface-aided OFDM: A Fractional Programming Based Approach","authors":"Keming Feng, Yijian Chen, Yu Han, Xiao Li, Shi Jin","doi":"10.1109/VTC2021-Spring51267.2021.9449003","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9449003","url":null,"abstract":"Reconfigurable intelligent surface (RIS) is a low-cost device envisioned to achieve substantial promotion in both spectrum and energy efficiency in the future wireless communication systems. In this paper, we investigate the downlink transmission of the RIS-enabled orthogonal frequency division multiplexing (OFDM) system, and propose a low-complexity passive beamforming optimization algorithm to maximize the achievable sum-rate over all subcarriers. The passive beam-forming optimization is a NP-hard problem due to the RIS-induced non-convex unit modulus constraints. We conquer this difficulty by exploiting a fractional programming (FP) based approach combined with an efficient manifold optimization (MO) method. With the proposed low-complexity passive beamforming optimization algorithms and water-filling power allocation, the achievable sum rate can then be maximized through alternating optimization (AO). Simulation results indicate that the proposed AO based algorithm performs well in achieving high average sum-rate with a fast convergence rate.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133956127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A 2D Non-Stationary Channel Model for Underwater Acoustic Communication Systems","authors":"Xiuming Zhu, Chengxiang Wang, Ruofei Ma","doi":"10.1109/VTC2021-Spring51267.2021.9448976","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448976","url":null,"abstract":"Underwater acoustic (UWA) communication plays a key role in the process of exploring and studying the ocean. In this paper, a modified non-stationary wideband channel model for UWA communication in shallow water scenarios is proposed. In this geometry-based stochastic model (GBSM), multiple motion effects, time-varying angles, distances, clusters’ locations with the channel geometry, and the ultra-wideband property are considered, which makes the proposed model more realistic and capable of supporting long time/distance simulations. Some key statistical properties are investigated, including temporal autocorrelation function (ACF), power delay profile (PDP), average delay, and root mean square (RMS) delay spread. The impacts of multiple motion factors on temporal ACFs are analyzed. Simulation results show that the proposed model can mimic the non-stationarity of UWA channels. Finally, the proposed model is validated with measurement data.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"193 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134321315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reliability Enhancement by PDCP Duplication and Combining for Next Generation Networks","authors":"A. M. Ahmed, A. Patel, Mohammed Zafar Ali Khan","doi":"10.1109/VTC2021-Spring51267.2021.9449079","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9449079","url":null,"abstract":"User equipment (UE), in general, has access to multiple radio access technologies (RATS). Besides, secondary base-stations can also aid the UE’s communication. Thus data can reach the UE from the primary base-station via multiple secondary base-stations. Taking advantage of the benefits of using such multiple paths, we propose in this paper a cross-layer scheme that improves block error rate (BLER) and throughput. We propose data duplication and integration at the Packet Data Convergence Protocol (PDCP) sublayer of layer 2 for downlink operations of 4G LTE / 5G NR. At the PDCP of ENodeB (gnodeB), the PDCP protocol data unit (PDU) is duplicated and sent to the UE via various paths. All these PDUs have the same sequence number (SN). Data from various networks are aptly linked using the PDCP assigned SN at EnodeB to obtain a composite and improved version of the PDU at UE. Although the cross-layer technique involves new procedures when combining data at PDPCP, the average delay for a PDCP-based aggregation scheme is very small compared with the standalone scheme because of the significant improvement in the block error rate (BLER) provided by the scheme over the BLER of the traditional standalone system. Finally, the BLER improvement results in throughput enhancement.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113985899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Research on Power Distribution Method of OFDM System with Hybrid Energy Supply under Fast Fading Channel","authors":"Yipeng Liu, Zhicheng Dong, Wei Xiao, E. Panayirci","doi":"10.1109/VTC2021-Spring51267.2021.9448768","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448768","url":null,"abstract":"An adaptive power allocation by minimizing grid power consumption for the Orthogonal Frequency Division Multiplexing (OFDM) system with the hybrid energy supply under a fast fading channel is proposed in this paper. To solve the non-convex problem, two adaptation algorithms have been presented. The first is Lagrangian algorithm and the second is a successive convex approximation (SCA) algorithm. The theoretical analysis and simulation results show that the proposed algorithms are effective. Compared with traditional OFDM systems with grid energy supply only, the proposed algorithms can reduce the power consumption of the grid. Also, different proposed algorithms have different performance. Lagrangian algorithms with higher computational complexity have better performance. However, there is a trade-off between computational complexity and performance.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"450 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114001987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Deep Reinforcement Learning for Edge Computing Resource Allocation in Blockchain Network Slicing Broker Framework","authors":"Yu Gong, Siyuan Sun, Yifei Wei, Mei Song","doi":"10.1109/VTC2021-Spring51267.2021.9449081","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9449081","url":null,"abstract":"With the constant development of 5G technology, such as softwareization and virtualization, the novel concept of network slicing has been appeared. Blockchain is a decentralized technology for managing transactions and data which can ensure the security of transaction. Recently, the classical mobile network introduces a new role such as network slice agent to provide slices for one or across multiple operators, providing services for users or vertical industries over a larger time and space range. In this paper, we propose the blockchain network slicing broker (BNSB), an intermediate broker, which receive resources request and response then allocation resources between Network Slice Tenants (NST) and then schedule physical resources from Infrastructure Provider (InP) through smart contracts. The topology information is obtained according to the Complex Network theory and the value of nodes is defined according to their importance. In addition, Deep Reinforcement Learning algorithms is used to explore the optimal policy under the condition of meeting the service Level Agreement (SLA).","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"10 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114019966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation on a Drone Classification Method Using UWB Radar Image Recognition with Deep Learning","authors":"Daiki Kawaguchi, R. Nakamura, H. Hadama","doi":"10.1109/VTC2021-Spring51267.2021.9448946","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448946","url":null,"abstract":"This paper presents a method for recognizing various drones from images of ultra-wideband (UWB) radar range profile by using a convolutional neural network (CNN) model. CNN is a Deep learning algorithm that provides high accuracy for image recognition tasks. We investigated the recognition performance for five types of drones with different shapes, sizes, and the number of rotor blades (Matrice 600, 3DR Solo, Phantom 3, Mavic pro, and Bebop drone) and a radio-controlled flapping bird (Bionic bird). As a result, we have confirmed that our presented method can recognize each target with high accuracy of 90 % or more.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115079346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Remun Koirala, B. Uguen, D. Dardari, H. Wymeersch, B. Denis
{"title":"Direction Aided Multipath Channel Estimation for Millimeter Wave Systems","authors":"Remun Koirala, B. Uguen, D. Dardari, H. Wymeersch, B. Denis","doi":"10.1109/VTC2021-Spring51267.2021.9448770","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448770","url":null,"abstract":"In this paper, we present a low-latency direction assisted channel estimation algorithm suitable for millimeter wave (mm-Wave) systems. First, during the beam training procedure, we perform angle of departure (AoD) and angle of arrival (AoA) measurements with their corresponding variances and based on them, we design both downlink and uplink beams. We then perform signal measurements with these beams and accordingly design the sensing matrix, while also iteratively refining the angle estimation and the beams for the next measurements accordingly. Finally, exploiting both the sparseness and the intrinsic geometric nature of the mm-Wave channel, we apply compressive sensing tools so as to complete the estimation procedure. Simulations show that the corresponding estimation error decreases rapidly in comparison with other conventional approaches.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"2004 28","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114128871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Baghdad Hadji, A. Aïssa-El-Bey, L. Fergani, M. Djeddou
{"title":"Channel Estimation Using Multi-stage Compressed Sensing for Millimeter Wave MIMO Systems","authors":"Baghdad Hadji, A. Aïssa-El-Bey, L. Fergani, M. Djeddou","doi":"10.1109/VTC2021-Spring51267.2021.9448773","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448773","url":null,"abstract":"Millimeter-wave (mmWave) and multiple-input multiple-output (MIMO) combination technologies have at-tracted extensive attention from both academia and industry for meeting future communication challenges and requirements. As a viable option to deal with the trade-off between hardware complexity and system performance, hybrid analog/digital architectures are regarded as efficient mmWave MIMO transceivers. While acquiring channel state information (CSI) is a challenging task to design the optimal beamformers/combiners, especially in mmWave communications due to a lot of challenges. Fortunately, the sparse nature of the channel allows to leverage the compressed sensing (CS) tools and theories. However, the critical challenge to develop a CS-based formulation for estimating the mmWave channel is the codebook design (sensing matrices) and its pilot symbol numbers. In this paper, we proposed a multistage CS-based algorithm to estimate the channel explicitly using pilot and data symbols which enable increasing the number of measurements to enhance the estimation accuracy and maximize the spatial diversity by reducing the overlapping between training beams. Simulations confirmed that our proposed method has the best results compared to the existing methods based on codebook schemes.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116731792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Particle Swarm Optimization Algorithms for Altitude and Transmit Power Adjustments in UAV-Assisted Cellular Networks","authors":"Shourya Shukla, Rahul Thakur, Swati Agarwal","doi":"10.1109/VTC2021-Spring51267.2021.9448994","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448994","url":null,"abstract":"After providing ubiquitous and high-speed network connectivity to mobile users, cellular operators are exploring unique domains to extend the reach of cellular networks. In this direction, the use of Unmanned Aerial Vehicles (UAVs) has received significant interest from both industry and academia. UAVs equipped with a transceiver module can act as relays and/or base stations to extend coverage and provide line-of-sight connectivity to mobile users, especially during emergencies such as earthquakes and floods. To reap the gains of UAV-based cellular networks, deployment and operational parameters of UAVs such as altitude and transmit power need to be carefully controlled. In this paper, we propose two algorithms for independently adjusting the altitude and transmit power of UAVs to maximize the system throughput. These algorithms are based on Particle Swarm Optimization and are shown to quickly converge to a better solution when compared to the traditional fixed altitude and fixed transmit power approaches.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115305892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}